Note: Descriptions are shown in the official language in which they were submitted.
21 64001
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PCT/~P1~5101 19~ 1
CABLE-DRIVEN WINDOW LIFT
Description
The invention concerns a cable-driven window lift defined in the preamble
s of claim 1.
Illustratively such a cable-driven window lift is described in the German
patent document A-l 33 25 837, wherein it evinces a drive mechanism comprising a cable
drum for alternatingly winding and unwinding a cable for instance held in the form of a
loop. Starting from the said drive with two outputs, the cable runs in each case in a cable
.0 sheath or hose to a deflection site between which, when the lift is in the assembled
position, the cable runs in an essentially vertical direction parallel to a window-pane
guide-rail holding a pane-actuator. The cable is linked to the actuator and as a result a
corresponding actuator rotation entails alternating winding and unwinding of the cable
on the drum and hence to lifting and lowering the pane. Each of the dr*e outputs is
~s fitted with a conll)ression spring resting between the drive housing and the end face of
the particular cable sheath. These springs assure that any slack in the cable shall be
elimin~ted form the overall system and accordingly the cable shall remain tensioned
under all operational conditions at least in the region of the rails holding the actuator.
The springs of the known window lifts are designed in such manner that their spring force
iS less than the force arising at the actuator and displacing the pane. Some play material-
izes in the known window lifts when drive rotation is reversed, and said play includes the
displacement path of the springs: Before there is motion of the actuator, i.e. of the pane
when there is reversal of the direction of pane displacement, first the previously relaxed
spring will be compressed, while the other spring will be relaxed. However such an
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PcT/Ep9slo119~ 2
arrangement is disadvantageous with respect to handling because the displacement path
of the two compression springs is added to the inherent play of the drive, and consequent-
ly the pane will remain in its previous position when there is reversal of motion within
an angle of rotation of 20 to 40 .
s The known window lift incurs another drawback in that when substantial
forces are applied to the pane, the spring in the cable lifting portion is totally compressed
and the pane may drop, namely by exactly the amount of said spring displacement. This
displacement may be 5 to 6 mm and suffices to produce a small gap between the pane
and the seal of the door frame. Clattering and undesired wind noises may arise.
.0 In the light of the above, the object of the invention is to improve a window
lift of the initially cited kind making possible the raising and lowering of the window pane
in substantially play-free manner and thereby to avoid clattering and wind noise. --
This problem is solved by features of claim 1.
As regards claim 2 and vehicle window-lifts driven by electric motors
providing a short descending excursion of the pane, a reversed design of the compensating
springs is recommended. Such short-excursion descents are used without additional pane
guide-frames in particular in such vehicles as coupes, the pane in its closed position being
pressed against a seal mounted in the vicinity of the vehicle roof. To avert excessive
mechanical stresses on the seal, the pane initially is lowered a slight amount by the motor
drive during opening and closing and then is displaced in controlled manner while the
door is closed into the closed position, i.e. to rest against the roof-side seal. This short
stroke of the pane moves by about 10 to 15 mm. If now on account of aging the cable
should be slack, then the spring mounted on the descending side of the cable must be
moved totally compressed until a descent of the pane starts at all. However, because the
` 2164001
PCTIE~85/01185 3
spring mounted in the cable descending portion and defined in claim 2 exerts a substan-
tial force, this spring will not be in the totally compressed state when the pane is in the
closed position. As a result no significant spring displacement takes place during lower-
ing, and thereby all slack is removed from the cable system.
s The invention also applies to a cable window-lift with a closed cable loop,
and in this case the springs are preferentially mounted at the drive outputs and rest on
one side against the drive housing while acting on the other end against the end face of
each sheath enclosing the cable.
Obviously the invention also may be applied to a cable window-lift wherein
.0 said cable is interrupted in the vicinity of the actuator, the cable ends so formed being
individually connected to the actuator. In the latter case the springs rest against the
actuator and drive the cable ends illustratively fitted with terminal nipples.
Further objects, advantages and features of the present invention are
elucidated in the following description of illustrative embodiments and in relation to the
.s enclosed drawing.
All described and/or graphically shown features per se or in arbitrary
pertinent combinations do form the object of the present invention, also independently
of their consolidation in the claims or their inter-relations.
Fig. 1 is a schematic view of an illustrative embodiment of a cable window
lift of the invention,
Fig. 2 is an illustrative embodiment of a cable window-lift driven by a
motor, and
Fig. 3 is still another illustrative embodiment of a cable window-lift of the
invention.
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PCT/EP95101 190 4
The cable window lift of Fig. 1 comprises a drive 1 with an omitted cable
drum to alternatingly wind and unwind the cable 2. The cable drum is linked to an
omitted crank bolt receiving a handcrank in the instance of the presently shown embodi-
ment of a mechanical window lift. Starting at the drive 1, the cable 2 runs from two
outputs 7 and 8 each time inside a cable sheath 4 to a deflection means 6 possibly in the
form of a roller, whereupon the cable 2 runs parallel to a rail 5 which shall be affixed to
the vehicle door. A window pane actuator 3 is present at the rail 5 and is linked to the
cable 2.
A co~ uression spring 9, 10 is present at the outputs 7, 8 of the drive 1, each
,0 spring resting between the housing 11 of the drive 1 and the end face of the particular
cable sheath 4. These springs 9, 10 ensure that any slack in the cable 2 shall be removed
from the overall system, whereby the cable 2 shall be tensioned under all operational
conditions at least in the region of the rail 5.
The design of the springs 9, 10 in known window lifts is such that their
.s spring force is less than the pane-moving force acting on the actuator 3. If the actuator
3 of Fig. 1 were displaced upward, i.e., if the pane were moved into the closed position,
then the spring 9 affixed in the cable lifting cable portion 15 would be compressed or
even possibly compressed totally together, whereas the spring in the cable descending
portion 16 would be relaxed, and slack present between the output 7 and actuator 3
would be eliminated. If next the pane shall be opened by moving the actuator 3 down-
ward, then the spring 10 present in the cable descending portion 16 shall be compressed
while now the spring 9 in the lifting cable portion 15 relaxes, and any slack between the
output 8 and the upper end of the actuator 3 is elimin:lted. In the known window lifts
some play is produced when the drive 1 implements a reversal in rotation, said play
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PCT/ E P0 S/0 11911 5
furthermore including the displacement path of the compression springs 9, 10: Before the
actuator 3 and hence the pane will move when there is reversal of direction of rotation,
first the previously relaxed spring 9 or 10 shall be colllpressed, during which procedure
the particular other spring 10 or 9 shall relax. This mech~ni~m however is disadvanta-
s geous in handling the pane because this pane will remain in its previous state through an
angle of rotation for instance 20 to 40~ .
In order to elimin~te the play caused by the compression springs 9, 10 from
the overall system, the window lift of the invention calls for a spring force exerted by the
coll.pression spring 9 affixed to the upper output 8 when in the assembly position of the
.0 cable window lift which shall be larger than the force of displacement of the pane and
larger than the spring force of the spring 10 affixed in the cable descending portion 16.
When the actuator 3 moves downward, the spring 10 affixed in the cable descending
portion 16 will be compressed totally, as in the state of the art, while the colllpression
spring 9 affixed in the lifting cable portion 15 relaxes. Upon a subsequent upward
s movement of the actuator 3 however, the compression spring affixed in the lifting cable
portion 15 remains in its relaxed or nearly relaxed position on account of its higher spring
force, and this spring 9 practically eliminates all slackness from the system, as a result of
which the lower spring 10 remains totally or nearly totally compressed. Because the
spring 9 affixed in the cable lifting portion 15 is compressed not at all or only slightly
toward its state of total compression, practically no play is produced when reversing the
direction of motion. These conditions are maintained as long as the pane remains below-
its upper limit position.
Once the pane has reached the upper limit position and thereby has entered
the door-frame seal while the crank should somehow be rotated further in the closing
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direction, then with a corresponding drive-torque, the compression spring 9 will be
pressed together and may assume its totally compressed state. In such a case the spring
10 mounted in the cable descending portion 16 relaxes in order to elimin~te the cable
slack from system. In fact a somewhat enlarged dead-zone arises during the subsequent
s reversal of motion of the pane. However this dead zone is compensated by the advantage
that when the pane is in its upper limit position, ie the closed position, if accidentally
knocking the handcrank toward the pane descending direction, the pane will remain in
its closed position until the compression spring 9 with the larger spring force has relaxed,
the compression spring 10 then passing into its totally compressed mode.
,0 If now for any reason an external force larger than that from the co.l.ples-
sion spring 9, for instance caused by potholes and the like, acts on the pane, then, as
regards the known window lifters, the compression spring 9 is abruptly compressed to
totality, as a result of which the pane descends by the excursion of this compression spring
9. The excursion may amount of 5 to 6 mm. This displacement is sufficient to generate
.s a slight gap between the pane and the door-frame seal, entailing clattering and/or
undesired wind noise. On the other hand, in the invention the force of spring 9 is larger
than that produced by the pane and the frictional forces in the case of opposing forces
caused by a rising motion and the compression spring 9 is capable to elastically absorb
such pane impacts, and as the force exerted on the pane decays, the prevailing force from
the compression spring 9 will again move the pane into its initial position, that is in its
closed position. Hence clattering and wind noise are eliminated.
In the case of an electrical window lifter, the compression spring 9 with its
higher force and in the lifting cable portion 15 will act additionally as an impact damper
when the pane hits the upper closed position.
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PCT/EP95/01191~ 7
Another advantage offered by such a window lift with the spring 9 in the
cable lifting portion 15 than that of the spring in the cable descending portion 16 is that
the torques are approxim~tely equal for the lifting and descending motions of the pane.
In known window lifts on the other hand the difference in torques between up and down
pane motions is about 50 ~o. Accordingly the operators of manual window lifts frequently
are under the impression -- especially when first the pane has been lowered and then is
to be raised again -- that the window lift is unusually difficult to operate. Therefore the
automobile industry already has required the most equal possible torques for up and
down motions. Approximate equality of the two said toralues is created in the invention
by mounting a spring 9 with a larger force in the cable lifting portion 15, whereas, during
the descending motion, the spring 9 with the higher force causes increased friction by the
cable 2 in its sheath 4. By using springs 9 and 10 of different spring forces, dispersion of
torque caused by differential frictions between pane and door or pane seal also are made
smaller.
The window lift of Fig. 2 is designed to be powered by an electric motor.
The components corresponding to the embodiment of Fig. 1 are denoted by the same
references and their description need not provided in detail again.
As regards the embodiment of Fig. 2, the springs 9, 10 are selected in such
manner that the spring 10 in the cable descending portion 16 compressed when the pane
iS being opened evinces a force which is larger than the force of the pane weight and of
the friction due to displacing said pane, and also larger than the lifting force from the
spring 9 in the cable lifting portion 15. Such a design relating to the springs 9, 10 is
especially appropriate for window lifts driven by electric motors and with short pane
excursions. Such short pane excursions sometimes are used in vehicle doors lacking
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PCT/~Pg5/011~ 8
additional guide frames for the window pane in order to achieve improved door closing.
In such vehicles lacking window guides, the pane frequently will be pressed against a seal
present in the vicinity of the vehicle roof. If then the door were opened while the pane
is in the closed position, the seal would be unduly stressed. Therefore the procedure has
been adopted to use a switch at the door lock so that, when it is opened and closed, first
the pane shall be lowered by a short path and then upon closing the door the pane shall
driven in controlled manner into the closed position, that is the position in which it makes
contact with the roof-side seal. The path followed by the pane during the downward short
excursion is between 10 and 15 mm. If now slack is present in the cable on account of
aging, then, as regards the known window lifts with the pane moving down, the spring 10
first must be totally compressed until the downward motion of the pane begins at all.
However, because in the invention the spring 10 of Fig. 2 mounted in the cable descend-
ing portion 16, that is that spring mounted at the ~utput 7, evinces a larger force, it will
not be totally colnpressed when the pane is in the closed position. No significant spring
displacement takes place when the pane descends out of the closed position, and there-
fore any slack is removed from the system.
It is true that in this design, that is in the selection of the springs 9 and 10,
the cable friction is increased when the pane is rising, but the larger torque encountered
is without significance in motor-driven window lifts that are required for instance for
short-e~cursion panes. Another advantage of mounting the stronger spring in the cable
descending portion 16 is that when the pane meets the lower limit stop, that is when it
reaches its open position, impact damping is achieved, such damping being more impor-
tant in electrically driven window lifts than that of the pane upward motion. Thereby as
well the mechanical load on the cable will be minimi7ed.
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PCT/EP95101190 9
The embodiment of Fig. 3 concerns a window lift wherein -- contrary to the
embodiments of Figs. 1 and 2 -- the cable 2 is interrupted in the vicinity of the actuator
3. The free ends of the cable are fitted with nipples 14 inserted into a nipple chamber
13 of the actuator 3. In this embodiment the springs 9, 10 are located inside the nipple
chamber 13 to compensate any slack in the cable system, and said springs rest against the
actuator 3, i.e. the wall of the nipple chamber 13 while acting by their other ends on the
nipples 14 at the associated cable ends. Depending on the particular application, a larger
force may be exerted by the spring 9 in the cable lifting portion 15 which is compressed
in the closed pane position, or the compressed spring 10 in the cable descending portion
16 may evince the larger spring force in this embodiment just as in those described
further above.
The components of Figs. corresponding to those of Figs. 1 and 2 also are
identified by the same references and accordingly no further discussion of these identical
components is required. However the embodiment Fig. 3 comprises an assembly plate-
or sheetmetal 12 linked to the rail 5 for ease of transportation.
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List of component references
drive
2 cable
3 actuator
S 4 sheath
S guide
6 reversal means
7 output
8 output
' 9 spring
spring
11 drive housing
12 assembly plate or sheetmetal
13 n;pple box
14 nipple
cable lifting portion
16 cable descending portion -
